Occupant restraint system

ABSTRACT

A vehicle body occupant restraint system includes a source of pressure fluid, an inflatable occupant restraint cushion, and a passage communicating with the cushion and having an orifice of predetermined flow area. An end wall of the pressure vessel includes a pair of plugs, each comprising an externally threaded hollow body threaded into a threaded opening of the end wall. The bores of the plugs are located parallel of each other and communicate in series with the passage orifice through an antechamber of a member containing the passage and opening to the bores of the plugs. The bore of one plug is of lesser predetermined flow area than the passage orifice, and the bore of the other is of greater predetermined flow area than the passage orifice. Each plug bore is closed to the pressure vessel by a diaphragm rupturable by electrically fired detonators. At vehicle impacts above a predetermined minimum level of intensity and below a predetermined maximum level, the detonators of the one plug are fired and the bore of the one plug controls the flow rate to the cushion. Upon impact levels of intensity above the predetermined maximum, the detonators of both plugs are fired and the passage orifice controls the rate of flow to the cushion. The latter rate of flow is the normal rate of flow so that the cushion inflates during the normal time period. The former rate of flow is reduced so that the time period of inflation is increased.

United States Patent 1 Blanchard [54] OCCUPANT RESTRAINT SYSTEM [75]Inventor: Houston F. Blanchard, Greenfield,

Wis.

[73] Assignee: General Motors Corporation,

Detroit, Mich.

[22] Filed: Aug. 27,197]

[211 Appl. No.: 175,577

[52] U.S. Cl ..280/l50 AB, 222/3 [51] Int. Cl ..B60r 21/08 [58] Field ofSearch ..280/150 AB; 222/3; 137/67,

[56] References Cited UNITED STATES PATENTS 3,420,572 l/l969 Bisland..280/l50 AB X 3,495,675 2/1970 l-lass et al. ..280/l 50 AB X 3,532,35810/1970 Selwa et al..... ..280/l50 AB 3,582,107 6/1971 Goetz ..280/l50AB 3,622,974 1l/l97l Best et al ..280/l50 AB X 3,632,135 l/l972 Chute etal ..280/I50 AB 3,639,710 l/l972 Haruna et al ..280/l50 AB PrimaryExaminer-Kenneth H. Betts Assistant Examiner-George Steube Attorney-W.E. Finken et al.

[ Jan. 30, 1973 AB TK QT source of pressure fluid, an inflatableoccupant restraint cushion, and a passage communicating with the cushionand having an orifice of predetermined flow area. An end wall of thepressure vessel includes a pair of plugs, each comprising an externallythreaded hollow body threaded into a threaded opening of the end wall.The bores of the plugs are located parallel of each other andcommunicate in series with the passage orifice through an antechamber ofa member containing the passage and opening to the bores of the plugs.The bore of one plug is of lesser predetermined flow area than thepassage orifice, and the bore of the other is of greater predeterminedflow area than the passage orifice. Each plug bore is closed to thepressure vessel by a diaphragm rupturable by electrically fireddetonators. At vehicle impacts above a predetermined minimum level ofintensity and below a predetermined maximum level, the detonators of theone plug are fired and the bore of the one plug controls the flow rateto the cushion. Upon impact levels of intensity above the predeterminedmaximum, the detonators of both plugs are fired and the passage orificecontrols the rate of flow to the cushion. The latter rate of flow is thenormal rate of flow so that the cushion inflates during the normal timeperiod. The

former rate of flow is reduced so that the time period of inflation isincreased.

1 Claim, 2 Drawing Figures PATENTEB JAN 3 0 I975 I N VEN TOR.

OCCUPANT RESTRAINT SYSTEM This invention relates generally to vehicleoccupant restraint systems and more particularly to a multilevel vehicleoccupant restraint system including an occupant restraint cushion whichis inflatable from a source of pressure fluid at various rates inaccordance with predetermined levels ofintensity of vehicle impact.

Copending application Ser. No. 175,661, Thomas H. Vos, OccupantRestraint System, filed Aug. 27, 1971, discloses a multiple leveloccupant restraint system wherein the flow rate of pressure fluid to acushion and consequently the time period of cushion inflation is set ata predetermined level by selective operation of serially disposed flowcontrol orifices in accordance with predetermined levels of intensity ofimpact.

The system of this invention differs in providing selectively operableparallel disposed inlet orifices which communicate in series with anoutlet orifice communicating with the cushion. One of the inlet orificesis of lesser flow area than the outlet orifice and, when operative,controls the rate of flow of pressure fluid to the cushion andconsequently the time period of inflation thereof. This orifice isselectively operated by a control arrangement when the level ofintensity of impact is above a predetermined minimum and below apredetermined maximum. When the level of intensity is above thepredetermined maximum, the other inlet orifice is additionally operatedby the control arrangement to provide for increased flow of pressurefluid to the cushion so that the cushion inflates in the normal timeperiod. The other inlet orifice has a flow area greater than that of theoutlet orifice whereby the outlet orifice controls the rate of flow whenboth inlet orifices are operated. Each orifice is closed by a detonatorrupturable diaphragm. The detonators are electrically fired by a controlarrangement in accordance with predetermined levels of intensity ofimpact sensed thereby.

The primary feature of this invention is that it provides a multiplelevel vehicle occupant restraint system wherein a source of pressurefluid and an inflatable cushion are interconnected by selectivelyoperable parallel disposed inlet orifices communicating in series withan outlet orifice, one inlet orifice having a flow control area lessthan that of the outlet orifice and being selected by a controlarrangement to limit the rate of flow through the outlet orifice whenthe level of intensity of impact of the vehicle falls within apredetermined range, the other inlet orifice having a flow control areagreater than the one and the outlet orifice and being additionallyselected by the control arrangement to increase the rate of flow throughthe outlet orifice when the level of intensity is above thepredetermined range.

This and other features of the restraint system of this invention willbe readily apparent from the following specification and drawingswherein:

FIG. 1 is a view of an occupant restraint system according to thisinvention; and

FIG. 2 is a schematic of the control arrangement.

Referring now to FIG. 1 of the drawings, a pressure vessel designatedgenerally forms part of a conventional vehicle occupant restraintsystem. Since the details of such system are conventional and notnecessary to an understanding of this invention, they are not disclosedherein. Reference may be had to the aforenoted Vos application for suchdetails. Although a pressure vessel has been disclosed in conjunctionwith the subject occupant restraint system, it will be apparent, ofcourse, that a gas generator or an air-augmented system may likewise beused.

The cylindrical outlet neck 12 of the pressure vessel is internally andexternally threaded. The internal threads receive an externally threadedcylindrical closure 14 provided with a pair of threaded bores 16 and 18.A conventional diffuser and manifold assembly 20 includes a passage 22which communicates with an inflatable cushion, not shown. The manner inwhich passage 22 communicates with the inflatable cushion is not shownbut is conventional, and reference may be had to Ser. No. 142,533 Nollet al., filed May 12, 1971, and Ser. No. 11,189 Cole, filed Feb. 13,1970, now US. Pat. No. 3,610,657 for the details. The enlargedcylindrical end 24 of assembly 20 is internally threaded and receivesneck 12 as shown. Suitable seals may be provided between the assembly 20and the pressure vessel.

The threaded bores 16 and 18 each receive respective plug assemblies 26and 28. Such plug assemblies are the same in structure and function,although dimensionally different. The plug assembly 26 includes anexternally threaded plug body 30 which is received within bore 16 and ahex or similar head 32 engaging the outer wall of closure 14. The body30 includes an internal cylindrical bore 34 which opens at one endthrough the head 32 to the antechamber 36 defined by end 24 of assembly20. The other end of bore 34 is closed by an integral rupturablediaphragm 38 which may be conventionally scored in X or cruciformfashion. The diaphragm 38 blocks flow of pressure fluid between thepressure vessel 10 and the passage 22. A pair of conventionalelectrically fired detonators 40 are received within the bore 34 inengagement with the diaphragm 38. The detonators are retained in placeby conventional stemming material 42 which fills the bore.

The diameter of the bore 34 is less than that of the passage 22. Thus,if diaphragm 38 is ruptured, the rate of flow from the pressure vessel10 to the cushion through the passage 22 and the time period of theinflation of the cushion is controlled by bore 34. Bore 34 thus providesa first flow control inlet orifice in series with the outlet orifice 44of antechamber 36 or inlet of passage 22.

The plug 28 is structurally the same as the plug 26 but dimensionallylarger so that the bore 46 of such plug is of larger diameter than thediameter of bore 34 but of less diameter than orifice 44. Thus, whendiaphragm 48 is ruptured and pressure fluid flows from the pressurevessel 10 through both bores 34 and 46, the rate of flow and theconsequent time period of inflation of the cushion will be controlled bythe orifice 44. Bore 46 thus provides an inlet orifice in parallel withthat provided by bore 34 and in series with orifice 44.

The firing wires 50 of the detonators 40 and 52 of the detonators 54 ofplug 28 extend outwardly through conventional stemming material fillingbores 34 and 46 and are connected to a control system or arrangementschematically shown in FIG. 2 for firing the detonators in accordancewith the level of intensity of vehicle impact. The control system isonly briefly disclosed herein since it is the same as that disclosed indetail in copending application Ser. No. 175,5 76, Trevor 0. Jones,filed Aug. 27, 197i. The control system includes a pressure transducer56 actuated by an energy absorbing bumper system and an amplifier 58connected in series with an inertial sensor 60 across the detonators 40and a source of potential.

The pressure transducer 56 is actuated when the level of intensity ofthe impact forces applied to the impact bar of the energy absorbingbumper system exceeds the absorption capability of the system and thereis a likelihood or probability that deformation of the vehicle willoccur. The inertial sensor 60 is set at a level so as to be actuated bythe impact forces at approximately the same time that the transducer isactuated and prior to the onset of vehicle deformation. Thus, if thelevel of intensity of impact forces is above a predetermined minimumrequired for actuation and below a predetermined maximum, as will beexplained, the detonators 40 will be fired to remove the diaphragm 38.The flow of pressure fluid to the cushion will be controlled by bore 34and limited to a rate less than the normal flow rate so that the timeperiod of inflation of the cushion will be greater than normal.

The control system also includes a second inertial sensor 62 connectedin series with the first inertial sensor 60 and with the detonators 54across the source of potential. The sensor 62 is of the same structureas sensor 60 but is set so as to be actuated only when the level ofintensity of the impact forces is above the predetermined maximum. Insuch instance, the sensor 60 and the transducer 56 would likewise beenergized such that the detonators 40 would be fired concomitantly withthe detonators 54. The diaphragm 48. will thus be removed with thediaphragm 38 so that pressure fluid will flow from the pressure vesselthrough both bores 34 and 46. However, the flow rate through passage 22to the cushion is controlled by the orifice 44. Thus, the flow rate andthe time period of inflation are normal.

Thus, this invention provides an improved occupant restraint system ofthe multiple level type wherein a pair of inlet orifices are connectedin parallel with each other and in series with an outlet orifice toprovide for predetermined rates of flow of pressure fluid from a sourceto an inflatable cushion in accordance with predetermined levels ofintensity of vehicle impact.

I claim:

1. In a vehicle occupant restraint system including sensor meansoperative to sense the intensity of vehicle body impacts, a source ofpressure fluid, and an inflata ble occupant restraint cushion, thecombination comprising, an outlet orifice of predetermined flow areacommunicating with the cushion, a first inlet orifice communicating inseries with the outlet orifice and being of lesser predetermined flowarea than the outlet orifice to control the flow of pressure fluidtherethrough from the source to the cushion, a second inlet orifice inparallel with the first inlet orifice and in series with the outletorifice, the outlet orifice having a flow area less than that of thesecond inlet orifice to control the flow of pressure fluid therethroughfrom the source to the cushion, and control means directing the.

flow of pressure fluid through the first and second inlet orifices inaccordance with predetermined levels of intensity sensed by the sensormeans, the control means directing the flow of pressure fluid throughthe first inlet orifice upon a level of intensity above a predeterminedminimum and below a predetermined maximum being sensed by the sensormeans, the control means additionally directing the flow of pressurefluid through the second inlet orifice upon a level of intensity abovethe predetermined maximum being sensed by the sensor means.

1. In a vehicle occupant restraint system including sensor means operative to sense the intensity of vehicle body impacts, a source of pressure fluid, and an inflatable occupant restraint cushion, the combination comprising, an outlet orifice of predetermined flow area communicating with the cushion, a first inlet orifice communicating in series with the outlet orifice and being of lesser predetermined flow area than the outlet orifice to control the flow of pressure fluid therethrough from the source to the cushion, a second inlet orifice in parallel with the first inlet Orifice and in series with the outlet orifice, the outlet orifice having a flow area less than that of the second inlet orifice to control the flow of pressure fluid therethrough from the source to the cushion, and control means directing the flow of pressure fluid through the first and second inlet orifices in accordance with predetermined levels of intensity sensed by the sensor means, the control means directing the flow of pressure fluid through the first inlet orifice upon a level of intensity above a predetermined minimum and below a predetermined maximum being sensed by the sensor means, the control means additionally directing the flow of pressure fluid through the second inlet orifice upon a level of intensity above the predetermined maximum being sensed by the sensor means. 